Greenfinch photographed at CBNR on 22/4/2011 Photo: © Derek Bridel (visit site)

In Guernsey, the Greenfinch was recorded as common both by Smith and Dobson and its status in Guernsey seems to have changed little although numbers have probably declined over the past 50 years. Dobson records 'enormous flocks' occurring throughout the winter, associating with flocks of finches and buntings. Without any quantities it is difficult to assess whether any changes in numbers have taken place but flocks, larger than 200 birds, were rare in Guernsey towards the end of the twentieth century. These probably would not be described as 'enormous' by Dobson. In both Sark and Alderney, numbers have fluctuated. At the turn of the nineteenth century Greenfinches were probably fairly local and restricted on both islands. By the mid 1900s, it was absent as a breeding bird on Sark but fairly common in Alderney (Dobson). It is now a common breeding bird on Alderney but numbers of breeding birds do still fluctuate on Sark.

Greenfinches are still a common breeding species, passage migrant and winter visitor to Guernsey. During the 1989-91 GBBS, Greenfinches were recorded as breeding in every square. After the breeding season birds form flocks and parties up to 20-150 birds can be seen in gardens, weedy fields and along the coast where large numbers congregate and feed on the seed heads of Sea Radish. Large numbers pass through the islands in autumn, peaking in October. Ringing recoveries indicate a regular south-east/north-west migration pattern with birds many birds being caught in or originally ringed in south-east Britain. It is likely that some of these birds would be continental birds passing through England on to Guernsey and further south. Some of these birds remain and, in winter, birds can be found in almost every garden especially where supplementary food is provided. In some winters large influxes can occur and hundreds can occur in a single site.

Outside man's immediate environment, flocks also occur in other areas rich in seeds such as weedy fields. These tend to be fields in which vegetable or fodder crops are grown. After harvest in the autumn, some are left fallow and replanted in the spring. In the interventing period many weed species can grow up and set seed before cultivation the following spring.

The return passage takes place in throughout March and again there is a peak in the number of English controls caught at this time. Although this is likely to be indicative of migration, it is possible that Greenfinches are more likely to be caught coming to peanuts towards the end of the winter as food resources wil be lower. As with many passage migrants and winter visitors, the numbers wintering in the islands is very much dependent on conditions elsewhere and numbers can vary enormously between winters.